Add some extra security to my community website.

I am an IT expert in the university of Florida. Here, we have created a portal for students and teachers. So, that they could easily interact with each other, they could easily get their notes, know their test results, etc. They website portal is hosted on aws managed service provider. How the paas provider has ensure the security of it's managed platform. But, my seniors are still not satisfied and they are concerned about the security of their data. That's we are looking to add some extra security to the portal. Fortinet looks great to me but I am not sure if it is sustainable with the managed hosting provider. So, if any one here could guide me about the sustainability or have some better suggestions then please go ahead.